1. Field of the Invention
The present invention relates to a heavy-duty pneumatic radial tire and wheel rim assembly which can improve the ride comfort, stability of maneuverability, and decrease the partial wear or the like.
2. Description of the Prior Art
In general, a heavy-duty pneumatic radial tire adaptable to a bus, truck or the like, runs under a relatively large weight load. And especially, on the outside portion of the tire facing the outside of the vehicle in turning, an even larger load is applied and also, even at the tread portion, the shearing stress between the tread and load is increased. Therefore, especially as for the heavy-duty tire, it is preferred to have a high rigid region and anti-wear region at the outside portion of the tire in comparison to the inner portion of the tire.
However, the ordinary heavy-duty radial tire, is formed in bilateral symmetry with respect to the tire equator, in the meridian cross section of the tire, consequently, the tire lateral rigidity and anti-wear resistance and so on are substantially the same in both the inside portion and outside K portion. Consequently, when the tire is designed to obtain enough lateral rigidity so as to endure the cornering force, it decreases the ride comfort.
Since the weight o the heavy-duty tire is large, it is difficult to change the tire at the actual spot, even if the troubles such as puncture, valve failure, or the like occurs. Therefore, in the case of such a heavy-duty radial tire, as shown in FIG. 2, the support ring b to support the tire in a deflated condition is often inserted in the tire chamber i formed by the tire t and the wheel rim r. However, to install such a support ring r in the chamber i, it is often necessary to divide the rim into two halves r2, r2, and it makes for a complicated assembly of the tire with the rim and the support ring.
Accordingly, an object of the present invention is to provide a heavy-duty pneumatic radial tire and wheel rim assembly not exerting a baneful influence upon the ride comfort, improving the stability of maneuverability, and making it easy to assemble the support ring on the wheel rim.
The present invention is directed to a heavy-duty pneumatic radial tire and rim assembly having a support ring within the tire to support the tire in a deflated condition,
characterized in that said heavy-duty pneumatic radial tire being composed of a tread portion, sidewall portions extending from the both ends of said tread portion, and a pair of bead portion formed at each end of said sidewall portion,
the inner diameter Do of the outside bead portion, which is outside with respect to the vehicle, is substantially between 80 mm and 200 mm larger than the inner diameter Di of the outside bead portion.